Thermionic valve



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Filed July 21, 1925 Patented Dec. 28, 1926.

t1? 'QFFICE.

THERMIONIC VALVE.

Application filed July 21, 1925, Serial No. 45,123, and. in Great Britain December 19, 1924.

This invention relates to thermionic valves for use in wireless telegraphy and telephony and more particularly to valves of the type in which the electrodes are connected to contact pins mounted in a base member which carries the vitreous envelope.

The object of the invention is to provide an improved construction of valve of the character whereby self-capacity between the contact pins and associated connections will be reduced.

The base member in which the contact pins of the valve are mounted is usually made of insulating material which has a higher dielectric capacity than air so that a considerable self-capacity frequently exists between the contact pins and the connections leading therefrom to the electrodes.

According to the present invention a thermionic valve in which the electrodes are connected to contact pins mounted in an insulating base member is provided wherein the base member is hollowed out to form an air space between the contact pins for the purpose of minimizing the self-capacity between these pins.

An example of construction according to the invention is illustrated in the accompanying drawings in which Figure 1 is a vertical section through the valve,

Figure 2 is a transverse section and Figure 3 is a vertical section of a modified construction.

As shown in the drawings the vitreous envelope 1 which contains the-usual electrodes (not shown) mounted on a re-entrant tube 2, is fixed in a base member 3 of insulating material, such as ebonite, by means of suitable cementitious material as indicated at 4.

The base 3 is pierced with four apertures 5 in which the contact pins 6 are engagec, the apertures 5 being arranged so that the pins 6 take up the usual relative positions to enable them to engage correctly in a valve holder or plug.

In order to minimize the self capacity between the pins 6, the central portion of the base 8 is hollowed out as indicated at 7, the shape of the hollow or opening being preferably such as to provide gaps 7 a (see Figure 2) between adjacent pins 6 in addition to the gap formed by the main opening between pairs of opposite pins.

in the construction shown the leads from the electrodes to the pins 6 are conducted through the opening 7 and connected to the pins 6 points below the base member 3, but if desired the l ads could be conducted from the electrodes through the apertures 5 and connected to the upper ends of the pins 6 or they could be threaded through narrow apertures formed in the base member 3 adjacent the pins 6 and connected to the latter at points below the base member 3, the narrow ap rtures through which the leads are tbrea-zlct serving to hold these well apart and thus to reduce the capacity between them.

figure illustrates a modification of the invention in which it is applied to a valve adapted to be seated in a holder. The valve has a metal base 8 into which the vitreous bulb 9 is secured by cement 10, the base being closed by an insulated disc 11 in which contact studs 12 are carried. Through the centre of disc 11 an aperture 13 is formed communicating with the interior of the reentrant tube 14 of the bulb 9, this aperture having extensions between the studs 12 similar to those shown at 7 a in Figure 2.

I claim I 1. A thermionic valve comprising a vitreous container, an insulating base secured thereto and number of contact pins extending downwardly from said base, said base member being hollowed out to form a central air space between the contact pins for the purpose of reducing the capacity between. said pins.

2. A thermionic valve comprising a vitreous container, a base therefor, contact pins extending downwardly from said base, an insulating member within said base having a central aperture therethrough and apertures radiating from said central aperture between said contact pins and leading-in wires passing through said central aperture to connect the contact pins with the interior of the vitreous container.

In witness whereof I affix my signature.

WILLIAM RICHARD BULLIMORE. 

